Colorado State Soil

Seitz Colorado State Soil Soil Science Society of America Introduction Many states have a designated state bird, flower, fish, tree, rock, etc. And, many states also have a state soil – one that has significance or is important to the state. The Seitz is the official state soil ofColorado . Let’s explore how the Seitz is important to the state of Colorado! History In 1972, Seitz soils were first established in the area around Rio Grande County, Colorado. The soil got its name from the Seitz stream which was close to where soil scientists described the soil. The Seitz soil is the foundation for the grand and scenic views associated with Colo- rado and the large variety of outdoor recreational opportunities the state has to offer. What is Seitz Soil? The Seitz soils located primarily in southwestern Colorado are predominantly found at higher cooler elevations. These soils are found on hills, ridges, high valleys, and mountain slopes. Seitz soils are used as pastureland for grazing cattle, forestry, and outdoor recreation like hik- ing, camping, and winter sports because they are found in the mountainous areas of Colorado. Seitz soils are very deep, well drained soils developed in colluvium and slope alluvium. This means that as the rock on the mountainsides weather, the weathered material begins to creep and fall downslope due to gravity and water. As these materials reach a more stable position in the landscape, they accumulate and, over time, further weathering occurs, creating the Seitz soil. They are found on hills, ridges, mountain slopes, and valley sides, on slopes ranging from 2 to 65 percent. Every soil can be separated into three separate size fractions called sand, silt, and clay, which makes up the soil texture. They are present in all soils in different proportions and say a lot about the character of the soil. The topsoil (the layer of soil that we plow and plant seeds in) has a texture that is clay loam to sandy loam and usually has a lot gravel or rock fragments. It can be dark gray to black color when moist, and could be half rock fragments at the surface! The soil below where a farmer can plow (typically 20 cm) is topsoil. Topsoil typically has organic matter and fine roots that absorb water and nutrients for tree growth. The different horizontal layers of the soil are called soil horizons. Seitz soils typically have about 5 horizons. (Figure 1) The subsoil is the layers of soil below where fine roots grow. The subsoil is where large tree roots anchor the trees to the ground and in Seitz soils it has a yellowish-brown color, less organic matter and loses some properties which make it good for growing trees. For this reason preventing erosion is important for plant growth. Fig. 1. Seitz soil profile. Credit: NRCS Photo Soil Monolith: Chip Clark/Smithsonian Institution Fig. 3 Colorado Seitz soils provide sites for outdoor recreation in state and national forests and parks. further degraded over time, thereby making it less able to hold water and nutrients. The erosion of the top soil makes it even less suitable for plant and forest growth. The loss of soil and plant Fig. 2 Seitz soil series is the official state soil of Colorado. Credit: Smith- growth means less suitable land for the production of meat and sonian Institution. timber, as well as less land for wildlife. Because the soils are rocky and steep, they also are difficult sites to build homes and Where to dig a Seitz buildings. Without good management practices, soils such as Yes, you can dig a soil. It is called a soil pit and it shows you the Seitz are highly vulnerable. soil profile. The different horizontal layers of the soil are called soil horizons. This does not mean that other types of soil cannot Management be found there but that the Seitz is the most common. Seitz cov- Seitz soils are primarily used for the production of wood and rec- ers about 350,000 acres of land in 17 counties in south-central reation. The soils are poor in nutrients and generally not good for and southwestern Colorado. (Figure 2) This does not mean that growing crops. The combination of rocky soil and cold tempera- other types of soil cannot be found in those counties but the Seitz tures makes them unsuitable for farming. Seitz soils are typically is the most common. Other common mountainous soils found forested and can be a home to a wide variety of animals including in Colorado include Beeno, Fairfield, Ruby and Stunner series. grouse, mule deer, elk, and black bear. Seitz soils that have been While soils common to the eastern High Plains of Colorado in- cleared of forest and not replanted are used for grazing of animals clude Denver, Nunn, Olney, and Pleasant. because they can be used as pasture land. Importance and Uses Seitz Soil Formation Soil and land found in the mountainous areas of the US typically Before there was soil there were rocks and in between, ClORPT. do not have favorable properties for growing crops. Mountains Without ClORPT, there will be no soil. So, what is ClORPT? It soils tend to be more shallow and rocky than soils used in farm- is the five major factors that are responsible for forming a soil ing. However, these soils are usually great for the production of like the Seitz. It stands for Climate, Organisms, Relief, Parent wood, as a home to wildlife, for year- round outdoor recreation, material and Time. ClORPT is responsible for the development and as an area of land to capture and store drinking water in the of soil profiles and chemical properties that differentiate soils. soil. In Colorado Seitz soils provide jobs and money to the local So, the characteristics of Seitz (and all other soils) are determined economy through the production of timber via forestry activities, by the influence of ClORPT. Weathering takes place when envi- as well as sites for outdoor recreation in state and national forests ronmental processes such as rainfall, freezing and thawing act on and parks. (Figure 3) rocks causing them to dissolve or fracture and break into pieces. ClORPT then acts on rock pieces, marine sediments and vegeta- Limitations tive materials to form soils. When a soil cannot be used for one or more of the described functions, it is referred to as a limitation. Soil experts, called Climate – Temperature and precipitation influence the rate at Soil Scientists, have soils and have determined that Seitz soils which parent materials weather and dead plants and animals are suited for forestry, pastureland, and recreation. However, be- decompose. They affect the chemical, physical and biologi- cause it is primarily located on hill and mountain sides, the rocky cal relationships in the soil. Over time as a result of climate, soils can be easily eroded. This means that over time, the soil weathering and decomposition of plant material in soils de- can be carried down slope by heavy rains into nearby streams velop different colors at different depths. Seitz soils developed and rivers. Soil erosion can be much worse if there is excessive under cool summer climates with cold winters in the Colorado grazing by livestock or poor management of the soil during tim- Mountains. Because it is so cold, the soil does not breakdown ber harvesting. The result is that the nutrient poor topsoil can be as fast as soils in the High Plains of Colorado, where average temperatures are warmer. 2 Fig. 4 Relationship of soils, landform position (relief) and parent material. Seitz soils are located on the hill and mountain slopes. Credit: USDA- NRCS. Soil Survey of Saguache County, Colorado. Organisms – This refers to plants and animal life. In the soil, plant roots spread, animals burrow in, and bacteria break down plant and animal tissue. These and other soil organisms Fig. 5 Alluvial fan created. in the Lake Lawn flood of in Rocky Mountain speed up the breakdown of large soil particles into smaller National Park. Credit: Susan Fisk ones. Plants and animals also influence the formation and dif- ferentiation of soil horizons. Plants determine the kinds and erally, older soils have better defined horizons than younger amounts of organic matter that are added to a soil under nor- soils. Less time is needed for a soil profile to develop in a hu- mal conditions. Animals breakdown complex compounds into mid and warm area with dense vegetative cover than in a cold small ones and in so doing add organic matter to soil. Seitz dry area with sparse plant cover. More time is required for the soils support Engelmann Spruce, Ponderosa Pine, and Rocky formation of a well-defined soil profile in soils with fine tex- Mountain Douglas-fir trees. The trees are harvested for to tured material than in soils with coarse-textured soil material. make plywood or pulp to make things like paper. The effect of time on Seitz soils can be seen in many ways, including deposition of colluvial materials, multiple soil ho- Relief – Landform position or relief describes the shape of rizons, and dark colors at the soil surface as a result of plant the land (hills and valleys), and the direction it faces which decomposition. makes a difference in how much sunlight the soil gets and how much water it keeps. Deeper soils form at the bottom of the hill rather than at the top because gravity and water move Ecoregions, Soils and Land Use in Colorado soil particles downhill. Seitz soil has good drainage because it Within the borders of the Southern Rocky Mountains Physio- is located at higher elevations on mountain slopes (Figure 4).

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